refactor(api): create a new structure for the Go api (#94)

* refactor(api): create a new structure for the Go api

* refactor(api): update the way keyFile parameter is managed

api/unix_handler.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"net/http/httputil"
+)
+
+// unixHandler defines a handler holding the path to a socket under UNIX
+type unixHandler struct {
+	path string
+}
+
+// ServeHTTP implementation for unixHandler
+func (h *unixHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	conn, err := net.Dial("unix", h.path)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		log.Println(err)
+		return
+	}
+	c := httputil.NewClientConn(conn, nil)
+	defer c.Close()
+
+	res, err := c.Do(r)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		log.Println(err)
+		return
+	}
+	defer res.Body.Close()
+
+	copyHeader(w.Header(), res.Header)
+	if _, err := io.Copy(w, res.Body); err != nil {
+		log.Println(err)
+	}
+}
+
+func copyHeader(dst, src http.Header) {
+	for k, vv := range src {
+		for _, v := range vv {
+			dst.Add(k, v)
+		}
+	}
+}